Intel Core i7-1265U vs Intel Core i7-9800X Comparison

The Verdict

The benchmark data presents a surprisingly close contest between two processors from different eras and market segments. The Intel Core i7-1265U, a mobile part with a 15 W TDP, wins 7 of the 8 head-to-head benchmark comparisons, including every Cinebench test. The Intel Core i7-9800X, a desktop part with a 165 W TDP, wins only the Geekbench multicore test, but by a commanding margin of 39.6%.

The data suggests that the newer Alder Lake architecture in the i7-1265U delivers superior performance per watt and per clock in most measured workloads. The i7-9800X retains a clear advantage in Geekbench multicore, which appears to favor its higher thread count and quad-channel memory configuration. The i7-1265U leads in Geekbench singlecore by 14.4%, indicating a strong generational improvement in per-core efficiency.

For users prioritizing raw multithreaded throughput in Geekbench-style workloads, the i7-9800X remains relevant despite its end-of-life status. For everything else in the recorded benchmarks, the i7-1265U is the better performer, which is remarkable given its mobile form factor and dramatically lower power envelope.

Architecture Differences

The two processors represent distinct architectural generations and design philosophies. The Intel Core i7-9800X uses the Skylake-X architecture on a 14 nm process node, manufactured by Intel. It belongs to the Core i7 X-Series 9th Gen family, with the codename Skylake-X. The i7-1265U uses the Alder Lake architecture on a 10 nm process node, also fabricated by Intel, with the codename Alder Lake-U.

The core configurations differ significantly. The i7-9800X has 8 cores and 16 threads. The i7-1265U has 10 cores and 12 threads, which implies a hybrid arrangement with fewer threads than cores, typical of Alder Lake's performance and efficiency core design. The i7-9800X has a base clock of 3.80 GHz and a boost clock of 4.50 GHz. The i7-1265U has a base clock of 1800.00 MHz and a boost clock of 4.80 GHz, showing a much lower base frequency but a higher boost ceiling.

Cache hierarchies also differ. The i7-9800X has 64 KB of L1 cache per core, 1 MB of L2 cache per core, and 16.5 MB of shared L3 cache. The i7-1265U has 80 KB of L1 cache per core, 1.25 MB of L2 cache per core, and 12 MB of shared L3 cache. The i7-9800X has more total L3 cache, while the i7-1265U has more L1 and L2 per core.

Memory support separates the two clearly. The i7-9800X supports DDR4 memory with a quad-channel bus and a memory bandwidth of 85.3 GB/s. The i7-1265U supports both DDR4 and DDR5 memory with a dual-channel bus, and its memory bandwidth is not recorded in the database. Both lack ECC memory support.

PCIe capabilities differ by generation and lane count. The i7-9800X provides PCIe Gen 3 with 44 lanes from the CPU. The i7-1265U provides PCIe Gen 4 with 20 lanes from the CPU. The i7-1265U includes integrated graphics in the form of Iris Xe 96EU, while the i7-9800X has no integrated graphics listed. The i7-9800X has an unlocked multiplier; the i7-1265U does not.

The i7-9800X uses the Intel Socket 2066, while the i7-1265U uses the Intel BGA 1744 socket, confirming the former as a desktop platform and the latter as a mobile one. The i7-9800X is end-of-life and was released on 2018-10-18, while the i7-1265U is active and was released on 2022-02-22.

FAQ

Q: Which processor has a higher boost clock?

A: The Intel Core i7-1265U has a boost clock of 4.80 GHz, which is higher than the Intel Core i7-9800X's boost clock of 4.50 GHz.

Q: How do the two processors compare in single-core Cinebench R23 performance?

A: The i7-1265U scores 2195 in Cinebench R23 singlecore, while the i7-9800X scores 2176. This gives the i7-1265U a 0.9% advantage.

Q: Does the i7-9800X have integrated graphics?

A: No. The database lists no integrated graphics for the i7-9800X. The i7-1265U includes Iris Xe 96EU integrated graphics.

Q: What is the memory bandwidth difference between the two?

A: The i7-9800X has a rated memory bandwidth of 85.3 GB/s thanks to its quad-channel DDR4 support. The i7-1265U's memory bandwidth is not recorded in the database, and it uses a dual-channel bus.

Q: Which processor supports PCIe Gen 4?

A: The i7-1265U supports PCIe Gen 4 with 20 lanes from the CPU. The i7-9800X supports only PCIe Gen 3 with 44 lanes.

Q: In how many benchmarks does the i7-9800X win?

A: The i7-9800X wins exactly 1 of the 8 recorded head-to-head benchmarks, which is the Geekbench multicore test.

Specification Differences

The two processors differ across nearly every major specification field in the database.

• Cores: The i7-9800X has 8 cores; the i7-1265U has 10 cores.
• Threads: The i7-9800X has 16 threads; the i7-1265U has 12 threads.
• Base Clock: The i7-9800X has a base clock of 3.80 GHz; the i7-1265U has a base clock of 1800.00 MHz.
• Boost Clock: The i7-9800X has a boost clock of 4.50 GHz; the i7-1265U has a boost clock of 4.80 GHz.
• TDP: The i7-9800X has a TDP of 165 W; the i7-1265U has a TDP of 15 W.
• Socket: The i7-9800X uses Intel Socket 2066; the i7-1265U uses Intel BGA 1744.
• Architecture: The i7-9800X uses Skylake; the i7-1265U uses Alder Lake.
• Codename: The i7-9800X is Skylake-X; the i7-1265U is Alder Lake-U.
• Process Node: The i7-9800X uses 14 nm; the i7-1265U uses 10 nm.
• L1 Cache: The i7-9800X has 64 KB per core; the i7-1265U has 80 KB per core.
• L2 Cache: The i7-9800X has 1 MB per core; the i7-1265U has 1.25 MB per core.
• L3 Cache: The i7-9800X has 16.5 MB shared; the i7-1265U has 12 MB shared.
• Memory Support: The i7-9800X supports DDR4; the i7-1265U supports DDR4 and DDR5.
• Memory Bus: The i7-9800X is quad-channel; the i7-1265U is dual-channel.
• Memory Bandwidth: The i7-9800X has 85.3 GB/s; the i7-1265U has no recorded value.
• PCIe: The i7-9800X is Gen 3 with 44 lanes; the i7-1265U is Gen 4 with 20 lanes.
• Integrated Graphics: The i7-9800X has none; the i7-1265U has Iris Xe 96EU.
• Production Status: The i7-9800X is end-of-life; the i7-1265U is active.
• Release Date: The i7-9800X was released on 2018-10-18; the i7-1265U was released on 2022-02-22.
• Multiplier Unlocked: The i7-9800X is unlocked; the i7-1265U is locked.

Head-to-Head Benchmarks

The head-to-head benchmark results reveal a consistent pattern. The i7-1265U wins all six Cinebench tests, while the i7-9800X wins the Geekbench multicore test by a wide margin, and the i7-1265U wins Geekbench singlecore.

In Cinebench R15 multicore, the i7-1265U scores 1567 against the i7-9800X's 1553, a delta of 0.9% in favor of the mobile chip. In Cinebench R15 singlecore, the i7-1265U scores 221 against 219, again a 0.9% advantage. The margin is identical in Cinebench R20 multicore, where the i7-1265U scores 6530 and the i7-9800X scores 6474. Cinebench R20 singlecore shows 921 versus 913, another 0.9% win for the i7-1265U.

Cinebench R23 results follow the same pattern. In multicore, the i7-1265U scores 15549 versus the i7-9800X's 15416, a 0.9% difference. In singlecore, the i7-1265U scores 2195 versus 2176, once more a 0.9% gap. These consistently narrow margins suggest that the two processors deliver nearly identical performance in Cinebench workloads, with the i7-1265U holding a slight edge that likely stems from its higher boost clock and newer architecture.

The Geekbench results break the pattern dramatically. In Geekbench multicore, the i7-9800X scores 7488 against the i7-1265U's 5365. This represents a 39.6% advantage for the i7-9800X, the largest delta in either direction across all benchmarks. The 8-core, 16-thread configuration with quad-channel memory appears to give the i7-9800X a substantial edge in this particular multicore test.

Geekbench singlecore reverses the outcome. The i7-1265U scores 1633 against the i7-9800X's 1398, a 14.4% advantage for the mobile chip. This is the second-largest delta in the dataset and shows the i7-1265U's per-core strength.

The average benchmark scores from the broader database place the i7-9800X at 4455 and the i7-1265U at 4248. The i7-9800X sits at the 58th percentile of all CPUs, while the i7-1265U sits at the 57th percentile. In the nearest rivals list, the i7-9800X is closest to the AMD Ryzen 5 PRO 5650GE with a 0.3% difference, and the i7-1265U is closest to the Intel Xeon E-2378 with a 0.4% difference.

Where Each One Wins

The i7-9800X wins decisively in Geekbench multicore, where its 39.6% lead over the i7-1265U indicates a clear advantage for workloads that scale with many threads and benefit from the quad-channel memory bus. Users running heavily threaded applications that resemble Geekbench multicore patterns would prefer this processor. The 165 W TDP and desktop socket suggest it is designed for sustained, high-throughput computing in a stationary chassis.

The i7-1265U wins in every Cinebench test, although by narrow margins of 0.9% across the board. It also wins Geekbench singlecore by a substantial 14.4%. This points to a processor that excels in single-threaded responsiveness and in short-duration burst workloads. The 10-core hybrid design, with 12 threads total, appears to manage Cinebench's multithreaded rendering efficiently despite its 15 W TDP. The presence of Iris Xe 96EU integrated graphics and PCIe Gen 4 support makes it suitable for modern mobile systems where power efficiency and platform integration matter.

The data implies a clear usage split. The i7-9800X is the choice for users who prioritize raw multicore throughput in Geekbench-style tests and can accommodate a high-power desktop platform. The i7-1265U is the choice for users who value single-core performance, integrated graphics, and portability, while still delivering near-identical Cinebench scores to a much more power-hungry desktop part. The i7-1265U's wins in 7 of 8 benchmarks, including all Cinebench tests, suggest that architectural efficiency and higher boost clocks compensate for its lower base clock and smaller L3 cache in most measured scenarios.